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The Two Hosers Photo Show 16- Intro To Flash

In this episode Allan gets an update of the situation facing Canuckistan, Adam steps up to this week’s challenge with a bag full of excuses, and The Two Hosers start down the winding path of mastering your flash.

3 thoughts on “The Two Hosers Photo Show 16- Intro To Flash”

you are correct regarding the blood vessels reflecting the light causing red eye:

from wikipedia:

We’ve all see photographs where the people in the picture have spooky red eyes. These are photos taken at night with a flash. Where do the red eyes come from?

The red color comes from light that reflects off of the retinas in our eyes. In many animals, including dogs, cats and deer, the retina has a special reflective layer called the tapetum lucidum that acts almost like a mirror at the backs of their eyes. If you shine a flashlight or headlights into their eyes at night, their eyes shine back with bright, white light. Here is what Encyclopedia Britannica has to say about the tapetum lucidum:

Among many nocturnal vertebrates the white compound guanine is found in the epithelium or retina of the eye. This provides a mirrorlike surface, the tapetum lucidum, which reflects light outward and thereby allows a second chance for its absorption by visual pigments at very low light intensities. Tapeta lucida produce the familiar eyeshine of nocturnal animals.
Humans don’t have this tapetum lucidum layer in their retinas. If you shine a flashlight in a person’s eyes at night, you don’t see any sort of reflection. The flash on a camera is bright enough, however, to cause a reflection off of the retina — what you see is the red color from the blood vessels nourishing the eye.

Love the show! I listen on my phone and bounce around the photos while on the web. For some reason, I associated the wrong picture with your voices. I’m getting it straight now, though. More Blue Steel!

I just discovered you guys a month ago and am going thru old episodes…

To add to this discussion, photographers can detect cancer thru red eye, or lack thereof. A healthy eye will reflect red due to light bouncing off the retina and coming directly back out and into the camera. A cancerous eye will reflect white.

Note that this is different than catch light of course, which is light reflecting off the surface of the eye. A person with this eye cancer will have one eye with the typical red eye while the other eye in the same photo will show white.